Microelectromechanical systems (MEMS) devices with embedded mechanical components include, for example, pressure sensors, accelerometers, gyroscopes, microphones, digital mirror displays, micro fluidic devices, and so forth. MEMS devices are used in a variety of products such as automobile airbag systems, control applications in automobiles, navigation, display systems, inkjet cartridges, and so forth. Capacitive-sensing MEMS device designs are highly desirable for operation in miniaturized devices due to their low temperature sensitivity, small size, and suitability for low cost mass production. A MEMS pressure sensor typically uses a pressure cavity and a membrane element, referred to as a diaphragm, that deflects under pressure. In some configurations, a change in the distance between two electrodes, where one of the electrodes is stationary and the other electrode is the movable diaphragm, creates a variable capacitor to detect deflection due to the applied pressure over an area.
As the uses for MEMS sensor devices continue to grow and diversify, increasing emphasis is being placed on the development of advanced silicon MEMS sensor devices capable of sensing different physical stimuli at enhanced sensitivities and for integrating these sensors (e.g., accelerometers, gyroscopes, pressure sensors, and the like) into the same miniaturized package. These efforts are primarily driven by existing and potential high-volume applications in automotive, medical, commercial, and consumer products. The integration of MEMS pressure sensors with other types of sensors (such as, accelerometers and gyroscopes) has posed particular challenges in terms of achieving the required enhanced sensitivities for such pressure sensors.